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KENTUCKY ROCK ASPHALT HOT MIX SURFACES

DATA ARE PRESENTED PERTAINING TO THE PROPERTIES OF MATERIALS IN KENTUCKY ROCK ASPHALT MIXTURES, AND OF CONSTRUCTION PRACTICES, COSTS, AND SHORT TIME PERFORMANCE OBSERVATIONS OF PAVEMENTS USING THE MIXTURES. THE ROCK ASPHALT CONTAINS ABOUT 3.8% BITUMENS AND IS CRUSHED TO PASS A 3/8 INCH SCREEN, 85/100 PENETRATION GRADE ASPHALT IS ADDED SO THE HOT-MIX CONTAINS A TOTAL OF BETWEEN 9-10 PERCENT ASPHALT. SOME PROBLEMS WERE ENCOUNTERED WHEN HEATING THE ROCK ASPHALT AND CARE WAS NEEDED TO PREVENT A BUILD-UP OF MATERIAL IN THE PLANT. THE PERFORMANCE OF PAVEMENTS USING THIS MIXTURE IS RATED AS FROM SATISFACTORY TO GOOD UNDER LIGHT TRAFFIC. SKID RESISTANCE, WHICH IS THE PRINCIPAL ADVANTAGE OF THIS MIXTURE, IS RATED HIGH-COEFFICIENTS OF 0.57 TO 0.72. THE REPORT ALSO TRACES THE DEVELOPMENT OF THE SPECIAL PROVISIONS TO THE SPECIFICATIONS WHEN THIS MATERIAL IS TO BE USED. /BPR/